He was primarily an actor in Bengali theatre, where he became a pioneering figure in Modern Indian theatre, when he founded the 'Little Theater Group' in 1947, which enacted many English, Shakespearean and Brecht plays, in a period now known as the 'Epic theater' period, before immersing itself completely in highly political and radical theatre. His plays became apt vehicle of the expression for his Marxist ideologies, visible in socio-political plays like, Kallol (1965), Manusher Adhikar, Louha Manob (1964), Tiner Toloar and Maha-Bidroha. He also acted over 100 Bengali and Hindi films in his career spanning 40 years, and remains most known for his roles in films like Mrinal Sen's Bhuvan Shome(1969), Satyajit Ray's Agantuk(1991) Gautam Ghose's Padma Nadir Majhi (1993) and Hrishikesh Mukherjee's breezy comedies such as Gol Maal (1980) and Rang Birangi (1983).
He receivedNational Film Award for Best Actor in 1970 and three Filmfare Best Comedian Awards. In 1990, the Sangeet Natak Akademi, India's National Academy of Music, Dance and Theatre, awarded him its highest award the Sahgeet Natak Akademi Fellowship for lifetime contribution to theatre.